Delay arming fuze



P 953 H-. BERZQF ET AL 2,651,993

DELAY ARMING FUZE Filed Jan. 35, 1950 I Harold Brzaf Bani: A. 30 87:9

AITURNE) Patented Sept. 15, 1953 DELAY ARMING FUZE Harold Berzof and Frank A. Rogers, Edgewood, Md., assignors to the United States of America as represented by the Secretary of the Army,

as trustee Application January 3, 1950, Serial No. 136,616

(Granted under Title 35, U. S. Code (1952),

see. 266) Claims.

The invention described herein may be manufactured and used by or for the Government, for governmental purposes, without the payment to us of any royalties thereon.

This invention relates to actuating devices in general, and more particularly has reference to actuating devices for projectiles.

Previous to this time, as in World Wars I and II and in training maneuvers of armed forces, numerous incidents have occurred wherein premature actuation of a fuze mechanism has detonated the complete round, with resultant infi1ction of serious casualties upon members of the mortar crew, gun crew, or other strategic groups operating these or similar ordnance pieces. The premature explosions of rounds often took place in the muzzle of a gun or mortar, or within close proximity of the muzzle, with corresponding danger to personnel in the immediate vicinity. In addition, a projectile leaving a bore or barrel might strike an object in the immediate vicin ty of the gun position and detonate with similar disastrous consequences to personnel in the approximate area.

This invention is intended to eliminate this hazardous condition by providing a fuze wh ch is incapable of being actuated during handling and for a safe period after the round has left the muzzle of the ordnance piece.

The present invention is directed primarily to fuzes for mounting on projectiles used in muzzle loading mortars, breech loading mortars, and guns, rockets, bombs, and other instrumentseinployed to obtain destructive results in military and peacetime practices. This device is illustrated as applied to a 4.2-inch chemical mortar shell fuze, which rotates due to rifiing in the barrel, but it will work equally well if no rotation or spinning motion of the round occurred upon lnltiation of its propelling charge. With minor modifications, the delay mechanism illustrated in this specific fuze is applicable to similar functions in artillery fuzes, rocket fuzes, bomb fuzes, and other actuating devices wherein a delay period is considered desirable to further improve design, or to insure safety of personnel controlling, handling, initiating, or otherwise efiectmg functioning of dangerous and/or destructive items or materials or mechanisms of a similar nature.

In general, the shock of movement or acceleration which attends the discharge and flight of a projectile is used to supply action which incites functioning of the delaying mechanism. After this action has taken place a specific time or distance must elapse before a lock or barrier is removed from the path of motion of the arming mechanism present in the fuze. During this time or distance it is impossible for the fuze to become armed, and therefore virtually impossible for the round to function, even due to impact against an object. After this safety period has passed, the arming lock is withdrawn and the arming mechanism may function in the manner for which it is designed.

An object of this invention is to provide a fuze which may safely be transported and handled.

Another object of this invention is to provide a fuze which is protected against inadvertent operation in the barrel of an ordnance piece.

Another object is to provide a fuze which is unaffected by shocks of movement or oscillation from firing the projectile, other than the motivating action from which it is designed.

Another object is to provide a fuze which is positively locked against inadvertent operation prior to firing and the functioning of which is insured after subjection to the normal shock or other action attending firing and flight of a projectile whereby the removal of the arming lock has been effected.

Still another object is to provide a fuze which will not function within a hazardous distance of the mortar or gun position, or personnel, but will function upon impact with the intended object upon completion of flight or trajectory.

Yet another object of this invention is to provide a fuze which will not arm prior to a specified time or distance, but will arm prior to attainment of intended objective, with resultant detonation of the round upon impact with this objective.

Yet another object is to provide a fuze with the above characteristics which will in addition permit the selective use of an instantaneous or a delayed action detonator.

Another object of this invention is to provide a fuze which possesses the characteristics of delayed or instantaneous action, in addition to a delay arming lock, and in which the desired action is easily selectable prior to insertion of the round in the mortar or sun.

An additional object of this invention is to provide a delay arming fuze in which this delay arming action, or mechanism, will function consistently with little change in the delay period or time despite being subjected to relatively wide variations in temperature.

Another object of this invetnion is to provide a fuze wherein the arrangement of the delay ecti 3 mechanism will eliminate any opportunity for p ture actuation- Another object of this invention is to provide an arrangement wherein the actuating of the arming mechanism will in no way impair the other parts of the fuze or hinder arming.

Other objects and advantages of the invention will become apparent from the following description, taken in connection with the .accom panying drawings in which:

Figure 1 illustrates a longitudinal cross-section view of a detonating fuze illustrating an embodiment of this invention.

Figure 2 is a traverse section of the fuze shown in Fig. 1, taken on the line 1TII of Fig. 1.

Figure 3 is a cross-sectional view of the fuze, taken on the line III-III of Fig.

Figure 4 is a sectional view taken on the line =Rigure-5 isa sectional view taken on the line l e-IV 9 Fig. 2.

Referring more particularly to the drawing, in which likenumerals indicate the same or similar elements: 1 represents a fuze which .fiqnsistsof a head porti'on l and a base portion 2 which combine to form an logival fuze'having a firing pin 3 located at the upper end of the head portion and a neck 4 located'at the'lower end of the base portion which is threaded as at 5 for threadedly engaging the fuze socket of a shell.

A horizontal bore I4 is centrally located in the base portion and extends almost clear through, as shown in Fig. 2, receiving therein a slider l5. Communicating with bore II are pin Swhich protrudeSthrough bore 46 into the slider'bore I Q :and is threadedl engaged with the" stem' 40 of "a 'bellows memb liquiwfined bellow s=g,and spring I which encircles the upper end of he lockpin and which is in compressionable contact the'base of the bellows. Pro- "above thbase, portion and threadedly recelved in bore 6 is a retainer, Hi. This retainer secures the'bellows and lock pin within the bore l6 and also houses a spring operated puncturing device I2 The puncturing device con ts of apin pointed cylinder which moves against aspi ing II and when the latter is compressed the cylinder point extends through an opening in the base of retainer II] to engage the upperend of bellows '8. The upper ends of retainer lll and cylinder [2 are pierced to receive ashear wire l'a" bywhich the cylinder is held in a s ate position prior to firing. The protrudin portion-of the retainer is received in an annular recess'in' the head when the fuze is assembled.

Vrtical bore [9,which communicates with slider bore 14, receivesthe stem of firing pin '3'," the latter having a sharp point 21 which extends into the slider bore.

Bo r 53 communicates with a counterbore 51 which in turn, houses the priming charge 50, whilebo're 53' houses lead cup '49. This is the usual arrangement for detonating the explosive mixtures in shells of this type. The priming charge and lead cup combined form the projectile actuating means. Horizontal bore 55 serves as a recess for the slider guide pin 35, centrifugal spring 36 against which it operates,

and the securing nut 51 therefor. Horizontal bor 56 serves as a recess for the setting device The head portion of the fuze is bored and counterbored about its central axis, as at l! and I8. Bore ll contains the firing pin spring 29 and the firing pin head or cap 2!. Bore 18 receives -the firing pin shoulder 22. This shoulder has "a-groove machined in it, as at 23, to

accommodatea retaining screw 24 which limits the movement of *the firing pin and thus prevents the firing pin assembly from leaving the fuze after the .round has been fired. A horizontal bore near the top of the head portion of the fuze communicates with openings in cap :2! when the said cap is positioned for such alignment, and'the combined bores accommodate a shear wire 26 which also passes through a horizontal bore in the'firing pin shoulder. This shear wire retains the firing pin 3 and :firing pin spring 20 in theneutral position untilit is cut or sheared by action of the firing pin'upon firing, or set baclnof the round.

The slider I5 is secured in bore l4'by retaining nut l6; slider spring 48 is positioned between the nut'andslider and is normally held under compression, thereby providing th im petus for the slider. The slider has numerous bores, as follows: '30 and 3! are vertical and spaced for permitting selective detonating action and contain instantaneous .detonator 2B and delay detonator 2-9, respectively. A'm'illed slot 32 at the innermost and top portion of the :slider receives the lock pin Band thereby-controls the movement of'the slider. An additional'vertical bore 53 is located on the top side'of the slider and is in alignment with the vertical bore I9 when the slider'is locked by pin 9. This bore receives the-point of'firing pin "21 and thus gives an added safety featurewhen the complete'fuze is assembled. 'A'longitudinal groove 34 is located on the slider in a planewhich is clockwise from the plane of bore 33, as'viewedin Fig.5. This groove 34 is further pierced by bore 31 and receives the combination centrifugal pin and slider guide pin 35 when in the unarmed position. 'When the projectile is in flight, the pin will be forced outwardagainst spring Hauntil it contacts the boss on nut 51, at 'whichtime it will ride in groove. The pin will be Withdrawn from the locking position only'if suilicient rotationalvelocity is attained'to permit it to compress centrifugal spring 35. Directly opposite groove there are located longitudinal grooves 52a and 5211, which are of different lengths. These-two grooves areconnected by an arcuate groov 'in which the pin of setting device 5| rides. The length of the grooves is such that when the pin of setting device 5l is aligned with groove52ct, delayed detonator 29 will align itself with firing pin stem 2! when the slider moves to the armed position; and similarly, when the setting device is aligned with groove 52b, the instantaneous detonator 28 will be brought under the firing pin stem.

The setting device 5lc0n'sistsof a rivet-like member having a pin 5l'a' mounted on the head portion 5lb and radiallyset off'from'the'center thereof. The device is turnably secured in bore 56 by the use of a'split ring Washer 57 and screw sleeve '58, in a manner well known in the art. Thus, by turning the shank 5Ic of the rivet like member, pin 5la "will revolve'in thearcuate groove connecting grooves 52a and 52b. The end of shank 5lc is slotted so as to receive a screwdriver or other instrument for turning the said device.

The lock assembly comprises a. flexible envelope, or bellows 8 fabricated from metals or other nondistortable materials and having an integral head 38, which may or may not have a thinned section, dependent upon the material and dimensions of the bellows. The bellows is made rigid by filling with an incompressible liquid. The lower corrugation 39 of the bellows is attached to a combined shoulder and stem 40 by soldering or other means. A vertical bore 4| through stem 40 permits this bellows 8 to be filled with a liquid 42 of properties which have been predetermined and are acceptable for temperature ranges over which the fuze is to function, so that the fluid will at all times remain in the liquid state, will be incompressible, for the purpose in question, and will be acceptable for storage in the bellows over long periods of time. Liquids such as water have been eifective under limited conditions, while for wider application compounds which are liquid over a wider range of temperatures are desirable. One such compound is tributyrin or glycerol tributyrate, which has a boiling point of 599 F. and a melting point of less than 103 F. These liquids may be mixed with other liquids in which there is mutual solubility, so as to vary the viscosity and other properties, as will be understandable to one skilled in the art. We do not wish to limit ourselves to use of the liquids named, but merely to disclose them by way of examples. A plug 43 is forced into the filling bore and functions to insure retention of the liquid within the bellows. The lock stem and cap 9 is then attached to the Shoulder and stem 40 by means of screw threads 44.

The manner of operation may be readily under-- stood by having reference to the drawings, wherein the fuze is shown with the parts in the unarmed position. The slider l5 carrying detonators 28 and 23 is rested against lock pin 9 and is pierced by firing stem 21 in neutral bore 33 and by guide pin 35 in the alignment recess 34 and neutral bore 31. It is to be noted that stem 2! extends only part of the way into bore 33, and similarly, firing pin shoulder 22 has freedom of movement within bore Hi. This is to permit a small initial movement of the firing pin against spring 20 upon impelling the charge whereby wire 26 is cut. There are, therefore, three locks, 9, 21 and 35, when the fuze is finally assembled in the neutral position. The bellows being filled with an incompressible liquid 42 and assembled in the bore 6 forces pin 9 into bore I4 against the compressible spring 1, the latter being compressed to a predetermined degree.

Upon firing, or set back, puncturing device I2 shears wire l3, compresses spring ll, pierces a hole in bellows head 38, and is returned to the 6 centrifugal 1601: pm 35 have both been withdrawn from their respective receptacles within the detonator slide l5.

Also upon firing, or set back, the weight of the firing pin assembly 3 causes the firing pin cap to cut shear wire 26. During flight of projectile, when the period of increased acceleration, or what is commonly known as set back, has passed, firing pin spring 20 advances firing pin 3 into its armed position, thereb withdrawing stem 21 from bore 33 in slider and thus removing an additional obstruction to arming the fuse. This may take place in a brief interval of time, possibly when the shell is near the muzzle of the gun after firing the round. Also upon firing, when a sufilcient and redetermined rotational velocity has been attained by the round, the force developed by the centrifugal original position by the action of spring I l. Fluid 42 will then escape through the pierced bellows,

permitting the compressed spring I to expand and compressing the bellows with a corresponding withdrawal of lock pin 3 from slider slot 32. The size of the opening in the bellows is controlled with reference to the characteristics of the fluid 42 and therefore a finite predetermined time is required for the withdrawal of the lock pin. Slider I5 is free to move to the selected armed position, which has been designed previously by rotating indicator 5! into alignment with either em or 5|b, motivated by slider spring 48, provided that the firing pin stem 21 and pin will prove sufiicient to compress spring 36- and the said pin will be removed from its locking position in bore 31 and serve merely as a slider guide in groove 34 for alignment purposes; the boss on nut 51 serving to limit its outward movement. This centrifugal arming feature may be eliminated in shells which do not incur marked rotation within the gun or in flight, in which case the pin 35 would be in the groove 34 prior to firing and bore 31 would be eliminated.

It is therefore clear that the three safety locks have been withdrawn by the actions attendant upon the normal firing of the round and the fuze is prepared for point detonation upon impact with an objective.

Upon impact of the projectile with an objective, the cap 2! and firing pin 3 are forced downward, bringing point 21 into contact with the desired detonator charge and causing explosion thereof. The explosion of the detonator charge ignites the lead cup 49 and priming charge 50 in alignment therewith and, in turn, the components of the projectile.

It is to be noted that look pin 9 requires a finite, or comparatively extended, period of time subsequent to firing of the shell before it is removed as an arrester in th path of the slider. Thus the possibility of premature detonation is completely eliminated. In addition, the other safety features eliminate accidental detonation during handling, transporting, etc. In addition, the delay arming mechanism is relatively unaffected over a wide range of temperatures, to the extent that the delay arming period or distance suffers relatively small change due to wide variations in temperature conditions to which it may be subjected.

While we have shown and described a preferred embodiment of this invention for a specific application, it should be understood that this does not confine us to the precise details of construction herein set forth, by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the .art, without departing from the spirit of this invention.

We claim:

1. A free flight delay arming fuze of the class described, comprising in combination; a casing, a firing pin within the casing and slideable relative thereto, projectile actuating means spaced apart from the firing pin along the axis of slide thereof; casing walls forming a horizontal bore intermediate of the said firing pin and projectile actuating means; a slider in said bore, means to impel the slider in the bore, a detonating charge carried by said slider and normally being out of alignment withjthe :firing pin-andprofiectile actuengageabl'e with said. slider to arrest the impellingthereof, means tending to move the-lock pin out of engagement with said slider, rigidmeansacting thereon to prevent this disengagement and s'et v back actuated means operable to effect the slow collapse of thesaid rigidmemher and thereby permit the disengagement of said pin from said slider, saidirigid means com'prising 1a flexible bellows: :fi'll'edlwith: incompressible Lflmdand said set back-actuated means comp-risia-movable puncturing device located forward 20f: the:- bellows and within puncturing distance thereof.

'2. "free flight delay arming time of the class described, comprising in combination; a casing, a firing pin within the casing and slideablerelative thereto, projectile actuating means spaced apart from the firing pin along the axis of slide thereof casing Walls forming a horizontal bore intermediate of thesaid firing pin projectile actuating means a1- s'lider in said bore; means to imp'el the slider in the bore, a detonating charge carried by said slider and normally heing'oub-of alignment with thefiring pin and projectile-actuating means; means to limit the travel distance of the slider'whereby the charge may be broughtinto 's'aidalignment and means to prevent the said alignment for'a period '01 time afterthe 'fuzehas left a'gumsaid means comprising'a mov-able'lockzpin' operable into and out of said bore and engageablewithsaidslider toarrest the itn'pellin'g thereof; means operable on said lock pin to disengage it from the said slider oomprising a flexible bellows-filled with an incon pressible liquid attach'edto the lockvpin, acornpressed spring' member encircling said lock pin and acting uponthe: base of said bellows, a retainer in pressingrelationship"with the said bellows-at'the en'dthereo'f removed from-the lock pin attachment, said retainer having. a small opening therein, a movable puncturing device-forward of, aligned with, and movable into said opening, holding means associated with said device and tending to prevent the movement thereof; device being of such a weight that upon set back it moves against the'last said means to puncture the bellows and permit the escape of the liquid and thereby the slow withdrawal=of the loekpin from engagement with the slider.

3. A fuze according to claim 1 wherein the and projectile actuating means; means to select'ively'lifrfit the travel" distance-of the slider whereby theipreferred charge may be brought inte's'aid alignment; andnrearrs to prevent the said 'a-l-ignment-"for perm-diorama after the time has left a gun, .sald 'means comprising a movable lock pin operable into "and out ofsai d bore and-engageable with said slider to arrest the impe'lling thereof, m' eans' tending 'to'move the lock pin out of en gagernent "with "said slider", rigid means acting thereon to' prevent this disengagement and set back" actuated means o erable to effect the slow collapsebfthe said rigid member and thereby permit the disengagement of said pin from said 'sli'der;.'s'ai'd I'ig'i'dmeanscomprising a flexible 'bellowsn'lled" with an incompressible "flu-id anzrsaid set bani actuated means comprising a movable anuwlth'inipunctunn distance thereof.

'5'. A freefiight-delay arming ruzeer the class described, comprisin combination; a casing", a, firingpin within the casing and slideable relative thereto, proj'ect'ile 'actuating means spaced-apart fr'omthe'fi'ring pin along the axis of slide thereof casing walls folriihl'g a horizontal bore intermediate-or thesaid firing pin and projectileactua't'ing' means; a slider in said bore me'ans t'o impel 'tliesliderin the bore, a detonatin'g charge'carried s'aidslider' and normally being-out of alignment with the-"firing pin and projectile actuating means; r'nea-ns for preventing rotation of said slider within the bore andduring itstravel therein comprising wallson slider forming a longitudiiial groove thereon, amo v'able pin carried by the casing and receivable 'in the-said groove and tension means holding the pin in saidgroove; means to limit the travel distance of the-slider whereby the "charge may be brought into said alignment, and means to prevent the said aligninenti'or' a-pe'riod oiT'tim'e after the fuze' has left a gun, sa'idmeans comprising a movable lock pin operable iiitoand out'of said bore :and engageable with" saidslider to arrest the impelling thereof, means=tendingto move the lock pin out of engagement with saidslider, rigid means acting thereon to'prevent this disengagement and set backa'ctuated means operable to eifect' the slow collapse of the said rigid member and thereby permit the disengagement of' said pin from said slider, s'aid rig-id means comprising a flexible bellows filled'with an incompressiblefluid and said set back actuated means comprising a movable puncturingdv-ice'loc'atedforward of the bellows I and I 'within puncturing distance thereof.

movable puncturing device has means operable thereon to withdra'wthe said device-from the bellows after puncturing it whereby a larger escape area is exposeclto the liquid.

4. A free flight delay arming fuze of the class described, comprisingincombination;.a casing,

a firing pin within the casing and slideable relative thereto, projectile actuating means spaced HAROLD BERZOF. FRANK AL'ROGERS.

Referenees Cited :in the file of this patent UNITED STATES PATENTS Number Name Date 895,135 Meigs one. Aug. 18, 1903 1,472,941 Schneider i 1- Nov. 6-, 1923 1,933,603- ITeitscheid; Nov. 7, 1933 2,113,052 Woodbe'rry May 24, 1938 2,}3 7f7 ,l 74 -Parker May 29, 1945 2,455,95s Taylor Dec. 14, 1948 FOREIGN-PATENTS mber i r Dai' 257,335 GreatBri'tain Aug; 27, 1926 308,238 Italy May 30', 1933 mally being outof alignment withv the firing pin 7 

